Add incremental skill catalogs behind skill_catalog_deltas (#57262)

## What changed

- Add the disabled-by-default `skill_catalog_deltas` feature flag to append new and updated skills without repeating unchanged catalog entries.
- Share a cumulative metadata budget across executor, cloud, and host catalogs, preserving usage across turns and resume. Removals emit no update and do not refund budget.
- Rebuild the current catalog and reset its budget after compaction, including any required skill root mappings in updates.

## Testing

Add unit and integration coverage for update costs, shared source budgets, feature rollback, and catalog updates across resume and compaction, with a request-history snapshot.

GitOrigin-RevId: e88b4265d7361498113d43fdc2e0260a9f930bbc

codex-rs/cli/src/main.rs

@@ -2167,6 +2167,9 @@ async fn run_debug_prompt_input_command(
     codex_skills_extension::install(&mut extensions, |config: &Config| {
         codex_skills_extension::SkillsExtensionConfig {
             include_instructions: config.include_skill_instructions,
+            catalog_deltas_enabled: config
+                .features
+                .enabled(codex_features::Feature::SkillCatalogDeltas),
             max_context_tokens: config.skill_max_context_tokens,
             bundled_skills_enabled: config.bundled_skills_enabled(),
             cloud_skill_enabled: config.cloud_skill_enabled,